Electric-arc device



Sept. 22, 1925. 1,554,720

. 0. v. FERGUSQN v "nmzcmrc .ugc' nlvlcn Original Filed Dog. 3, 1918' A/ka/i AIefd/ Inventor:

Charl es V. Ferguson His Attorhey.

Patented Sept. 22, 1925.

CHARLES V. FERGUSON, OF SCH Application filed December 3,

ENECTADY, NEW

YORK, ASSIGNOR T GENERAL ELEC- rnrc COMPANY, A conromrron on NEW YORK.

ELECTRIC-ARC DEVICE.

To all whom it may cohcern:

Be it known that I, CHARLES V. FERGUSON,

a citizen of the Um Schenectady, of New Yor 'ted States, residing at county of Schenectady, State have invented certain new and useful Improvements in Electric-Arc Devices, of which the following is a specification.

prove the efliciency and rectifying properties of incandescent cathode devices.

My invention comprises a method of 0 erating a thermionic discharge of arc-like character in the vapor 0 device of the described class having an anode f an alkali metal and a consisting of an alloy of alkali metal, the device being constructed to tion of said alkali metal by charge.

permit vaporizathe electric dis- The accompanying drawing illustrates an embodiment of my invention.

The drawing shows a device comprising a sealed envelope 1 consisting of hard glass, quartz, or other material which is chemically inert to heated alkali metal vapor. It may be either evacuated such as hydrogen, sure, for example cury pressure. The filament of refracto ample, as tungsten.

or 4 or 5 centimeters of meror may contain a gas argon, at sultable prescathode 2 consists of a ry metal, such, for ex- It is supplied with heatmg current by the leading-in conductors 3,

4, which may also consist of tungsten, and

are sealed as usual into a stem 5. The anode 6 consists in part at for example,

sium, the varied. I

dium and two parts least of an alkali metal,

an alloy of sodium and potaslproportions of which ave used with good success an alloy containing one part b may be weight ofsoby weig t of potassium.

As shown in the drawing a sufiicient amount operation of t e p device embod ticularly notewort v --of voltage the disc of alkali metal is present to permit of the a discharge from the cathode in alkali metal vapor.

my invention is paror its IOWVCODSIImPtIOD arge havm teristics 0 an are. For examp e, in-a device m whichthe gap between cathode and anode one volt.

said electrode "one ampere current value drop 0 the charac- 1918, Serial No. 265,086. Renewed March 13, 1924.

is about 1.0 cm. with a current of about one ampere, the observed potential drop is about The close proximity of the cathode and anode causes the discharge path to be Wholly enveloped by alkali metal vapor which is evolved from .the anode by the heat of the discharge, thus utilizing advantageously the low ionizing potential of alkali metal vapor.

A tube embod ing my invention is particularly applicable as a rectifier for automobile and other small storage batteries as well as for attachment to' direct current voltmeters to enable them to operate on alternating current. I

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. An electric discharge device comprising a sealed container, cooperating electrodes one of which is constituted by'a filament of refractory material and a quantity of alkali metal located in said container so close to that when said material is vaporized during operation sufficient vapor is provided to wholly envelope the discharge path between said electrodes at a pressure at which an arc-like discharge may be conducted therethrough at potentials ap proximating one volt.

2. An electric rectifying device comprising the combination of a sealed container, electrodes therein including a filamentary cathode consisting of refractory metal and an anode constituted by a body of alkali metal located so closely adjacent said cathode that by the vaporization of said metal sufficient vapor is produced to permit of the operation of an arc-like discharge therein with a voltage drop of the order of one volt for a current of about one ampere.

3. The method of operating an arc-like discharge between closely adjacent cooperating electrodes one of which emits electrons when heated which consists in supplying to the discharge path .between said electrode the vaporof an alkali metal at a sufficiently highpressure to-cause a discharge of about to have a potential about one volt.

In witness whereof, I have hereunto set my hand this 2nd day of December, 1918.

CHARLES v. FERGUSON. 

